$(function () {
  var width; var height; var largeHeader; var canvas; var ctx; var points; var target; var animateHeader = true

  // Main
  initHeader()
  initAnimation()
  addListeners()

  function initHeader () {
    width = window.innerWidth
    height = window.innerHeight
    console.log(height)
    console.log(width)
    target = { x: width / 2, y: height / 2 }

    largeHeader = document.getElementById('demo-canvas')
    //        largeHeader.style.height = height+'px';

    canvas = document.getElementById('demo-canvas')
    canvas.width = width
    canvas.height = height
    ctx = canvas.getContext('2d')

    // create points
    points = []
    for (var x = 0; x < width; x = x + width / 20) {
      for (var y = 0; y < height; y = y + height / 20) {
        var px = x + Math.random() * width / 20
        var py = y + Math.random() * height / 20
        var p = { x: px, originX: px, y: py, originY: py }
        points.push(p)
      }
    }

    // for each point find the 5 closest points
    for (var i = 0; i < points.length; i++) {
      var closest = []
      var p1 = points[i]
      for (var j = 0; j < points.length; j++) {
        var p2 = points[j]
        if (!(p1 == p2)) {
          var placed = false
          for (var k = 0; k < 5; k++) {
            if (!placed) {
              if (closest[k] == undefined) {
                closest[k] = p2
                placed = true
              }
            }
          }

          for (var k = 0; k < 5; k++) {
            if (!placed) {
              if (getDistance(p1, p2) < getDistance(p1, closest[k])) {
                closest[k] = p2
                placed = true
              }
            }
          }
        }
      }
      p1.closest = closest
    }

    // assign a circle to each point
    for (var i in points) {
      var c = new Circle(points[i], 2 + Math.random() * 2, 'rgba(255,255,255,0.3)')
      points[i].circle = c
    }
  }

  // Event handling
  function addListeners () {
    if (!('ontouchstart' in window)) {
      window.addEventListener('mousemove', mouseMove)
    }
    //        randomRefresh();
    window.addEventListener('scroll', scrollCheck)
    window.addEventListener('resize', resize)
  }
  function randomRefresh () {
    	setInterval(randomPosition, 5000)
  }
  function randomPosition () {
    	var wid = $(window).width()
    	var height = $(window).height()
    	var x = wid * Math.random()
    	var y = height * Math.random()
    	changePosition(x, y)
  }
  function changePosition (x, y) {
    	target.x = x
    target.y = y
  }
  function mouseMove (e) {
    var posx = posy = 0
    if (e.pageX || e.pageY) {
      posx = e.pageX
      posy = e.pageY
    } else if (e.clientX || e.clientY) {
      posx = e.clientX + document.body.scrollLeft + document.documentElement.scrollLeft
      posy = e.clientY + document.body.scrollTop + document.documentElement.scrollTop
    }
    changePosition(posx, posy)
  }

  function scrollCheck () {
    if (document.body.scrollTop > height) animateHeader = false
    else animateHeader = true
  }

  function resize () {
    width = window.innerWidth
    height = window.innerHeight - 2
    largeHeader.style.height = height + 'px'
    canvas.width = width
    canvas.height = height
  }

  // animation
  function initAnimation () {
    animate()
    for (var i in points) {
      shiftPoint(points[i])
    }
  }

  function animate () {
    if (animateHeader) {
      ctx.clearRect(0, 0, width, height)
      for (var i in points) {
        // detect points in range
        if (Math.abs(getDistance(target, points[i])) < 4000) {
          points[i].active = 0.3
          points[i].circle.active = 0.6
        } else if (Math.abs(getDistance(target, points[i])) < 20000) {
          points[i].active = 0.1
          points[i].circle.active = 0.3
        } else if (Math.abs(getDistance(target, points[i])) < 40000) {
          points[i].active = 0.02
          points[i].circle.active = 0.1
        } else {
          points[i].active = 0
          points[i].circle.active = 0
        }

        drawLines(points[i])
        points[i].circle.draw()
      }
    }
    requestAnimationFrame(animate)
  }

  function shiftPoint (p) {
    TweenLite.to(p, 1 + 1 * Math.random(),
        		{
        x: p.originX - 50 + Math.random() * 50,
        y: p.originY - 50 + Math.random() * 50,
        ease: Circ.easeInOut,
        onComplete: function () {
          shiftPoint(p)
        }
      })
  }

  // Canvas manipulation
  function drawLines (p) {
    if (!p.active) return
    for (var i in p.closest) {
      ctx.beginPath()
      ctx.moveTo(p.x, p.y)
      ctx.lineTo(p.closest[i].x, p.closest[i].y)
      ctx.strokeStyle = 'rgba(156,217,249,' + p.active + ')'
      ctx.stroke()
    }
  }

  function Circle (pos, rad, color) {
    var _this = this;

    // constructor
    (function () {
      _this.pos = pos || null
      _this.radius = rad || null
      _this.color = color || null
    })()

    this.draw = function () {
      if (!_this.active) return
      ctx.beginPath()
      ctx.arc(_this.pos.x, _this.pos.y, _this.radius, 0, 2 * Math.PI, false)
      ctx.fillStyle = 'rgba(156,217,249,' + _this.active + ')'
      ctx.fill()
    }
  }

  // Util
  function getDistance (p1, p2) {
    return Math.pow(p1.x - p2.x, 2) + Math.pow(p1.y - p2.y, 2)
  }
})
